Mortality

Mortality

Major impediments to producing a complete picture of Indigenous mortality in Australia are the incomplete identification of Indigenous status in death records and the experimental nature of the recently adopted population estimates [1]. As a result of the incomplete identification of Indigenous status in death records, the 2,558 deaths registered in 2011 where the deceased person was identified as Indigenous is certainly an underestimate of the actual number of Indigenous deaths.

The extent to which the number of Indigenous deaths is under-estimated is not available for recent years [1], but the ABS does make adjustments to the number of registered deaths in preparing their estimates of life expectancy. It is likely that these adjustments are in line the ABS’s assessment of the completeness of recording of Indigenous deaths in 2006-2007, which was based on a comparison of deaths in those years with Indigenous status reported in the 2006 Census [2]. Based on this comparison, the ABS estimated that the Australia-wide level of Indigenous identification in deaths notifications in 2006-2007 was 92%, a level much higher than previous estimates (around 56%) [3].

The estimated completeness of identification of Indigenous people in death registrations has improved since the 1990s, mostly because of improvements in NSW and Qld, but there is still some doubt about the actual levels of identification [4]. As a result, the ABS notes that caution should be exercised in the interpretation of the estimates of Indigenous mortality, particularly estimates of trends over time [1]. This caution is reflected in recent ABS publications that do not include detailed tables of Indigenous deaths, nor information about overall death rates. As a result, there is no consistency about the extent of information available for recent years. Reflecting this, readers should be aware that the following sections vary in terms of the years to which they relate.

Age-standardised death rates

After age-adjustment, the death rate for Indigenous people living in NSW, Qld, WA, SA and the NT – the jurisdictions with adequate levels of Indigenous identification – was 1.9 times the rate for non-Indigenous people in 2006-2010 (Table 5) [6]. The rates for Indigenous people were highest in the NT (1,541 per 100,000) and WA (1,431 per 100,000).

Table 5: Age-standardised death rates, by Indigenous status, and Indigenous:non-Indigenous rate ratios, NSW, Qld, WA, SA and the NT, 2006-2010

Jurisdiction	Indigenous rate	Non-Indigenous rate	Rate ratio
Source: Australian Health Ministers’ Advisory Council, 2012 [6]
Notes: Rates per 100,000 are directly age-standardised using the 2001 Australia standard population Rate ratio is the Indigenous rate divided by the non-Indigenous rate Due to the incomplete identification of Indigenous status, these figures probably under-estimate the true difference between Indigenous and non-Indigenous rates
NSW	962	598	1.6
Qld	1,089	597	1.8
WA	1,431	574	2.5
SA	1,060	615	1.7
NT	1,541	645	2.4
NSW, Qld, WA, SA and the NT	1,151	597	1.9

Between 1991 and 2010, there was a 33% reduction in the death rates for Indigenous people in WA, SA and the NT; there was also a significant closing of the gap in death rates between Indigenous and non-Indigenous people during this time period [6].

Expectation of life

In 2009, the ABS revised its estimates for expectation of life at birth for Indigenous people [2]. After adjustment for the underestimate of the number of deaths identified as Indigenous, the ABS estimated that Indigenous males born in 2005-2007 could expect to live to 67.2 years, 11.5 years less than the 78.7 years expected for non-Indigenous males (Table 6). The expectation of life at birth of 72.9 years for Indigenous females in 2005-2007 was almost 10 years less than the expectation of 82.6 years for non-Indigenous females.

These revised estimates are significantly higher than previous estimates. Importantly, comparisons between the original and revised estimates should not be interpreted as a change in Indigenous life expectancy, but should be seen as the result of a revision in statistical methods used to calculate life expectancy [2].

Table 6: Expectation of life at birth in years for Indigenous people and the total population, by sex, selected jurisdictions, Australia, 2005-2007

Population	Males	Females
Source: ABS, 2009 [2]
Notes: The Australian Indigenous estimates are based on deaths in all states and territories
Indigenous
Australia	67.2	72.9
NSW	69.9	75.0
Qld	68.3	73.6
WA	65.0	70.4
NT	61.5	69.2
Total population
Australia	78.7	82.6

Age at death

For those jurisdictions with reasonable information about Indigenous deaths, the median age at death4 in 2011 for Indigenous males ranged from 50.3 years for those living in SA to 58.5 years for those living in NSW [1]. These levels were around 20 years less than those for non-Indigenous males, which ranged from 66.6 years (NT) to 79.7 years (SA). The median age at death for Indigenous females in 2011 ranged from 50.3 years for those living in SA to 66.2 years for those living in NSW. These levels were also around 20 years less than those for non-Indigenous females, which ranged between 73.5 years (NT) and 85.3 years (SA).

In 2007-2011, age-specific death rates were higher for Indigenous people than for non-Indigenous people across all age-groups, but the rate ratios were highest in the young and middle adult years (Table 7) [1]. (The rate ratios, based on the numbers of deaths registered, vary according to the levels of Indigenous identification (see above).)

Table 7: Age-specific death rates, by Indigenous status and sex, and Indigenous:non-Indigenous rate ratios, NSW, Qld, WA, SA and the NT, 2007-2011

Age-group (years)	Indigenous		Non-Indigenous		Rate ratio
	Males	Females	Males	Females	Males	Females
Source: ABS, 2012 [1]
Notes: Rates are per 1,000 Rate ratio is the Indigenous rate divided by the non-Indigenous rate Due to the small number of deaths registered in Vic, Tas and the ACT, information for these jurisdictions have been excluded
NSW
0	7	6	5	4	1.5	1.6
1-4	41	34	18	17	2.2	2.0
5–14	13	11	10	7	1.3	1.5
15-24	81	29	45	20	1.8	1.5
25-34	174	102	73	30	2.4	3.4
35-44	391	228	123	67	3.2	3.4
45-54	825	415	279	169	3.0	2.5
55-64	1543	1022	663	391	2.3	2.6
65+	4911	4431	4193	3732	1.2	1.2
Qld
0	8	7	5	4	1.6	1.7
1-4	50	56	22	17	2.3	3.4
5–14	18	18	12	10	1.5	1.9
15-24	126	71	56	25	2.3	2.9
25-34	249	123	86	34	2.9	3.7
35-44	515	304	128	68	4.0	4.5
45-54	929	562	270	159	3.4	3.5
55-64	1733	1384	640	372	2.7	3.7
65+	6117	4921	3993	3531	1.5	1.4
WA
0	10	5	3	3	3.4	1.8
1-4	63	48	22	12	2.8	4.0
5–14	38	29	8.8	9.3	4.3	3.1
15-24	241	106	56	26	4.3	4.1
25-34	406	219	89	36	4.6	6.1
35-44	834	510	121	66	6.9	7.7
45-54	1388	1021	260	153	5.3	6.7
55-64	2381	1671	579	343	4.1	4.9
65+	6380	5296	3819	3423	1.7	1.5
SA
0	6	7	4	3	1.5	2.4
1-4	0	90	26	14	0.0	6.5
5–14	17	17	7.9	7.4	2.1	2.4
15-24	166	96	55	20	3.0	4.8
25-34	314	188	88	36	3.9	5.3
35-44	684	517	147	79	4.7	6.5
45-54	1278	873	293	189	4.4	4.6
55-64	2131	1496	677	398	3.1	3.8
65+	4248	3872	4359	3911	1.0	1.0
NT
0	14	11	4	3	3.6	3.3
1-4	78	60	32	15	2.4	4.1
5–14	52	38	20	8.6	2.6	4.4
15-24	296	112	107	39	2.8	2.8
25-34	438	243	88	35	5.0	7.0
35-44	897	638	151	50	6.0	12.8
45-54	1596	1211	338	160	4.7	7.6
55-64	2920	2004	789	300	3.7	6.7
65+	6594	5531	3412	2563	1.9	2.2

Infant mortality

The infant mortality rate (IMR) is the number of deaths of children under one year of age in a calendar year per 1,000 live births in the same calendar year. For those jurisdictions with reasonable information about Indigenous deaths in 2009-2011, the highest Indigenous IMRs occurred in the NT; the lowest rate for Indigenous males was in SA (4.3) and for females was in WA (3.7) (Table 8) [1].

Table 8: Infant mortality rates, by Indigenous status and sex, and Indigenous:non-Indigenous rate ratios, NSW, Qld, SA, WA and the NT, 2009-2011

Jurisdiction	Indigenous		Non-Indigenous		Rate ratio
	Males	Females	Males	Females	Males	Females
Source: Derived from ABS, 2012 [1]
Notes: Infant mortality rate is the number of infant deaths per 1,000 live births Rate ratio is the Indigenous rate divided by the non-Indigenous rate The Indigenous rates are likely to be under-estimated, due to the incomplete identification of Indigenous status on births and deaths records Due to the small number of deaths registered in Vic, Tas and the ACT, these jurisdictions have been excluded
NSW	5.1	3.9	4.4	3.4	1.2	1.1
Qld	9.9	6.8	5.2	4.1	1.9	1.7
SA	4.3	6.6	3.6	2.9	1.2	2.3
WA	10.2	3.7	3.3	2.6	3.1	1.4
NT	14.3	11.6	3.0	4.2	4.8	2.8

In the five-year period from 2006 to 2010, Indigenous infants most commonly died from International Classification of Disease (ICD) ‘Conditions originating in the perinatal period’, including birth trauma, disorders relating to foetal growth, and complications from pregnancy, labour and delivery [6]. Indigenous infants died from ICD ‘Conditions originating in the perinatal period’ at twice the rate of non-Indigenous infants. The second most common cause of infant death was ICD ‘Congenital malformations’, for which Indigenous and non-Indigenous infants had similar rates (rate ratio of 1.2). The third most common cause of infant death was for ICD ‘Signs, symptoms and ill-defined conditions’, which includes sudden infant death syndrome (SIDS); Indigenous infants died at three times the rate of non-Indigenous infants (and, for SIDS alone, twice the rate).

From 1991 to 2010, there have been significant declines in IMRs for Indigenous and non-Indigenous infants in WA, SA and the NT: the rate has declined by 62% for Indigenous infants and by 43% for non-Indigenous infants [6]. The gap between Indigenous and non-Indigenous infants has closed substantially.

Causes of death

For deaths identified as Indigenous in 2006-2010, circulatory diseases (also known as cardiovascular disease, which includes heart disease and stroke) was the most common cause of death for Indigenous people living in NSW, Qld, WA, SA and the NT, accounting for 26% of Indigenous deaths [6]. The next most common causes of death were neoplasms (almost entirely cancer) (19% of Indigenous deaths) and external causes of death (injury) (15% of Indigenous deaths). For all major causes of death, Indigenous people died at higher rates than did non-Indigenous people (Table 9).

Table 9: Age-standardised death rates, by Indigenous status and cause, and Indigenous:non-Indigenous rate ratios, NSW, Qld, WA, SA and the NT, 2006-2010

Cause of death	Rate		Rate ratio
	Indigenous	Non-Indigenous
Source: Australian Health Ministers’ Advisory Council, 2012 [6]
Notes: Due to under-identification of Indigenous deaths, these rates are likely to under-estimate the true differences between the Indigenous and non-Indigenous populations Rates per 100,000 population have been standardised using the 2001 Australian population Rate ratios are the Indigenous rate divided by the non-Indigenous rate
Circulatory diseases	351	201	1.7
Neoplasms	245	178	1.4
Endocrine, metabolic and nutritional disorders (including diabetes)	118	22	5.4
Respiratory diseases	112	49	2.3
External causes	84	37	2.3
Digestive diseases	58	20	2.8
Kidney diseases	40	11	3.5
Nervous system diseases	27	24	1.1
Infectious and parasitic diseases	25	8.7	2.9
Conditions originating in the perinatal period	6.0	2.8	2.2
Other causes	85	43	2.0
All causes	1,151	597	1.9

In 2010, the leading specific causes of death differed for Indigenous males and females living in NSW, Qld, WA, SA and the NT [7]. For Indigenous male and females, the two leading specific causes of death were coronary heart disease (also known as ischaemic heart disease) followed by diabetes; the third leading cause of death were intentional self-harm (suicide) for Indigenous males and cerebrovascular diseases for Indigenous females. For non-Indigenous males, the leading causes of death were coronary heart disease, lung and related cancers, and cerebrovascular disease. For non-Indigenous females, the leading causes of death were coronary heart disease, cerebrovascular disease, and dementia and Alzheimer’s disease.

Maternal mortality

In Australia in 2003-2005 (the most recent period for which detailed data are available), six (10%) of the 60 maternal deaths where Indigenous status was known were of Indigenous women (Indigenous status was not reported in 8% of the deaths) [8].

Reflecting the higher rate of confinements among Indigenous women, the maternal mortality ratio for Indigenous women in 2003-2005 was 21.5 deaths per 100,000 confinements, almost three times higher than the ratio of 7.9 per 100,000 for non-Indigenous women (Table 10) (Derived from [8]). For direct maternal deaths, the ratio of 7.2 per 100,000 for Indigenous women was twice the ratio of 3.6 per 100,000 for non-Indigenous women.

Table 10: Numbers of confinements and maternal deaths, and maternal mortality ratios, by Indigenous status, Australia, 2003-2005

Indigenous status	Confinements	Maternal deaths	Maternal mortality ratio
Source: Derived from Sullivan, Hall, King, 2008 [8]
Notes: Maternal mortality ratio is the number of maternal deaths divided by the number of confinements (in 100,000s). Due to some uncertainty about the numbers of Indigenous deaths and confinements, some caution must be exercised in the interpretation of the ratios The non-Indigenous numbers and ratios include deaths for which Indigenous status was not known. This probably results in a slight, unknown over-estimate of non-Indigenous numbers and ratios, and a resultant under-estimate of the differences between Indigenous and non-Indigenous women
Indigenous	27,901
Direct and indirect maternal deaths		6	21.5
Direct maternal deaths		2	7.2
WA	745,347
Direct and indirect maternal deaths		59	7.9
Direct maternal deaths		27	3.6

Avoidable mortality

Avoidable mortality refers to deaths that could have been prevented with timely and effective health care, including early detection and effective treatment, as well as appropriate modifications of lifestyle behaviours (such as quitting smoking) [9].

In the five-year period from 2006 to 2010, there were 6,777 deaths from avoidable causes, representing almost three-quarters (74%) of the deaths among Indigenous people aged 0-74 years living in NSW, Qld, WA, SA and the NT (compared with 66% of non-Indigenous deaths) [6].

The age-standardised rates of avoidable deaths for Indigenous people were highest in the NT (787 per 100,000) and lowest in NSW (382 per 100,000) in 2006-2010 [6]. Indigenous people died from avoidable causes at 3.5 times the rate of non-Indigenous people living in NSW, Qld, WA, SA and the NT.

In 2006-2010, the most common conditions contributing to avoidable deaths among Indigenous people living in NSW, Qld, WA, SA and the NT were coronary heart disease (19%), cancer (17%), diabetes (10%), and suicide (8.5%) [6]. The death rates from avoidable causes were around twice as high for Indigenous people than for non-Indigenous people for cancer and suicide, four times as high for coronary heart disease, and 13.5 times as high for diabetes.

Between 1991 and 2010, there was a 24% decline in the death rate from avoidable causes for Indigenous people living in WA, SA and the NT [6]. The difference in rates between Indigenous and non-Indigenous people has decreased.

References

1. Australian Bureau of Statistics (2012) Deaths, Australia, 2011. Canberra: Australian Bureau of Statistics
2. Australian Bureau of Statistics (2009) Experimental life tables for Aboriginal and Torres Strait Islander Australians: 2005-2007. Canberra: Australian Bureau of Statistics
3. Australian Bureau of Statistics (2006) Deaths, Australia, 2005. Canberra: Australian Bureau of Statistics
4. Australian Bureau of Statistics (2011) Deaths, Australia, 2010. Canberra: Australian Bureau of Statistics
5. Australian Institute of Health and Welfare (2011) Principles on the use of direct age-standardisation in administrative data collections: for measuring the gap between Indigenous and non-Indigenous Australians. Canberra: Australian Institute of Health and Welfare
6. Australian Health Ministers’ Advisory Council (2012) Aboriginal and Torres Strait Islander health performance framework: 2012 report. Canberra: Office for Aboriginal and Torres Strait Islander Health, Department of Health and Ageing
7. Australian Bureau of Statistics (2012) Causes of death, Australia, 2010: Deaths of Aboriginal and Torres Strait Islander Australians. Retrieved 20 March 2012 from http://www.abs.gov.au/ausstats/subscriber.nsf/log?openagent&3303.0_12%20deaths%20of%20aboriginal%20and%20torres%20strait%20islander%20australians.xls&3303.0&Data%20Cubes&0BC29ACBD5D3F0D5CA257A24001D97D6&0&2010&22.06.2012&Previous
8. Sullivan E, Hall B, King J (2008) Maternal deaths in Australia 2003-2005. Canberra: Australian Institute of Health and Welfare
9. Page A, Tobias M, Glover J, Wright C, Hetzel D, Fisher E (2006) Australian and New Zealand atlas of avoidable mortality. Adelaide: Public Health Information Development Unit, University of Adelaide

Endnotes

4. The median age at death is the age below which 50% of people die. Because the measure partly reflects the age structures of the respective populations, it is a less precise measure than age-specific death rates, which are summarised below.

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